The present disclosure relates to a transmitted light volume adjusting apparatus and a transmitted light volume adjusting method.
In the related art, for example, in an apparatus that detects light of a digital video camera, a digital still camera, or the like, a neutral density filter (ND filter) is used so as to adjust the light volume incident on the apparatus. As an example of the ND filter, a technique is proposed in which the incident light volume is adjusted by combination of two polarizing plates. For example, JP 2001-160919A discloses a technique to arrange two polarizing plates on an optical axis of an imaging lens of an imaging apparatus and to rotate the polarizing direction (polarizing axis) of one of the polarizing plates with respect to the polarizing axis of the other polarizing plate, thereby adjusting the volume of light that travels on the optical axis.